Question

Which of the following are not true about hexagonal close packing?

• A. It has a coordination number of $6$
• B. It has $26$% empty space
• C. It is $ABCABC....$ type of arrangement
• D. It is as closely packed as body centred cubic packing

Answer 1

The correct option is A It has a coordination number of $6$

It has a coordination number of $6$
The hexagonal closest packed (hcp) has a coordination number of 12 and contains 6 atoms per unit cell.
In hexagonal close packing, layers of spheres are packed so that spheres in alternating layers overlie one another. As in cubic close packing, each sphere is surrounded by 12 other spheres.